As the simplest known aid for the visually impaired, magnifying glasses (including electronic ones) are known which magnify the text to be read (where the text to be read may be information which is represented on an information carrier, e.g. paper, in a visibly outstanding manner) to such an extent that visually impaired persons can read the text. Such magnifying glasses may comprise, for example, a camera, which can be placed on the text to be read, and an HMD device (Head-Mounted Display device) connected to said camera. In addition to magnification, false color representations are also known. Further, it is possible to provide a head camera which is mounted to the HMD device itself, instead of the camera which can be placed on the text. Such a device is described, for example, in DE 202 09 101 U1.
DE 201 13 278 U1 describes an electronic visual aid wherein the visual information is processed in terms of size, color, shape, contrast, extent, line width, number of lines, line transport, and is displayed, for example, via a projector. This is carried out such that the viewer can perceive an entire line of the visual object in sufficient shape, color and size.
In practice, however, it has turned out that, for example, the color of the text, the color of the background, as well as the reflectivity of the background and of the text itself may vary to a very great extent. A further influencing factor is, for example, the illumination of the text to be read. It is not possible to have one single setting of a visual aid that is optimal for all variations of the influencing factors.